This section is from the book "A Practitioner's Handbook Of Materia Medica And Therapeutics", by Thos. S. Blair. Also available from Amazon: A Practitioner's handbook of Materia Medica and Therapeutics.
Physostigma, Calabar Bean. This highly toxic drug has been employed in tetanus, tonic convulsions, severe neuralgia, phantom tumors, muscular rheumatism, and in strychnia poisoning, as well as in spasmodic conditions generally. Dose, extract, 1-10 to 1/4 gr., the average being 1/8 gr. The average dose of the tincture is 15 I; ec. tr., I to 3 I. See under "Eserine" also. Its average dose is 1-64 gr., and the maximum 1-30 gr. Before using this drug in the doses and for the indications given above, it would be well to study the physiologic action as related to the case in hand. It is a powerful agent, both for good and for harm, but usually for the latter.
In small doses (extract, 1-20 gr.; tr., 3 to 5 I; ec. tr., 1/4 I) it is employed in inactivity of the bowels with flatulence and muscular weakness, paretic diarrhea, diseases of the nerve centres, ocular paralysis, and writers' cramp. It has been commended in many other conditions by sectarian physicians. In general, it may be said that its influence in small doses is too uncertain to be depended upon, and it is little used in practice, although commended in the books. Eserine is highly useful in ophthalmic practice. The U. S. P. Physostigminae salicylas or sulphas are the salts commonly used, and are applied to the eye in 0.2 to 0.5% solution.